Magnetic anisotropy and process parameters in a nearly zero-magnetostriction metallic glass Fe4.5Co66Ni3.5Nb2Cr1B14Si9

Abstract

The role of the empirical cooling rate Λ/t (where Λ is the thermal conductivity of the chill block and t is the ribbon thickness) is investigated in a nearly zero-magnetostrictive metallic glass Fe_4.5Co₆₆Ni_3.5Nb₂Cr₁B₁₄Si₉. The average magnetostriction constant measured was −1.3 × 10⁻⁸. The glassy ribbons were prepared by planar flow casting using various process parameters at the Csepel Metalworks. Pure copper and Cu-2wt.% Be were used as the chill blockmaterial. The following parameters of the ribbons were measured: the actual chemical composition, the average thickness, the temperature coefficient of resistivity, the microhardness, the coercive forces measured parallel and perpendicular to the ribbon axis, the saturation magnetization, the saturation magnetostriction constant, the dynamic magnetic permeability and the quasi-static hysteresis curves. The preliminary search for correlation among the measured data has revealed that the in-plane anisotropy of the coercive force can effectively play the same dominant role as the empirical cooling rate. In this way, we conclude that in a zero-magnetostriction alloy the magnetic parameters are essentially determined by the anisotropies created during the production of the ribbons. The long-term room temperature aging of the ribbons was also investigated.